[Philip]

Thanks for the additional photos showing us the lock interior.

What you see is perhaps a North African- made version of the most common of the Portuguese-designed flint mechanisms. It's called a fecho de nó or "knot" lock. I can't explain the significance of the term, it appears to be period nomenclature and not a later collectors' neologism, like "miquelet" or "mortuary sword" coined generations after the fact.

Be that as it may, the essentials of the fecho de nó are a typical flintlock tumbler and sear system with half- and full cock detents. On a lock with external cosmetic or stylistic features that are typically Portuguese.

Rick points out that there is a similar-looking one that has a gravity- or thumb operated pivoting stop on the outside of the plate that serves as a safety, engaging a notch at the base of the cock. That type of lock is called fecho meio à portuguesa e meio à francesa, or lock half-Portuguese and half-French. It has a French-style tumbler and sear arrangement (though without half-cock notch) and the Portuguese pivoting safety which is seen on yet further variations of flintlock mechansms from this country. Please refer to post #14 for the late export example that he shared with us.

It's important to note that despite the Portuguese preference for these pivoting safeties, the behind-the-cock "dog" that was popular in parts of northern Europe (especially England) was not favored here.